A small update containing interface improvements and some low priority fixes.

- [interface] Planet list button selection persistent and greyed out if not selected.
- [interface] Added subsidies that are in effect to the List of Planets.
- [interface] Beautified menu audio options.
- [interface] Buttons color changed from yellowish to gold.

- [fix] Incorrect Admiral summon tooltip (also made the tooltip more descriptive).
- [fix] Audio rare crash fix (crash if no headphones plugged in/turned on if headphones are the only audio device, also added a warning if no device plugged in).